tntlogin: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/lib/rancid/bin/tntlogin - from package: rancid

You may install the required package with command apt-get install {package}

Error in other languages:
tntlogin: bevel nie gevind nie
tntlogin: comandă negăsită
tntlogin: comando não encontrado
tntlogin: commande introuvable
tntlogin: command not found
tntlogin: käsku ei ole
tntlogin: không tìm thấy lệnh
tntlogin: komanda nerasta
tntlogin: Kommando nicht gefunden.
tntlogin: kommandot finns inte
tntlogin: komut yok
tntlogin: nie znaleziono polecenia
tntlogin: níor aimsíodh an t-ordú
tntlogin: no se encontró la orden
tntlogin: no s'ha trobat l'ordre
tntlogin: opdracht niet gevonden
tntlogin: parancs nem található
tntlogin: perintah tidak ditemukan
tntlogin: príkaz nenájdený
tntlogin: příkaz nenalezen
tntlogin: команда не найдена
tntlogin: командата не е открита
tntlogin: 命令找不到
tntlogin: コマンドが見つかりません